Co and terpolymer reactivity ratios of chemically amplified resists

Publication date: 2 June 2017
Source:Polymer, Volume 118
Author(s): Narahari S. Pujari, Mingxing Wang, Kenneth E. Gonsalves
Resists are important multicomponent system require in microelectronic industry for fabrication of integrated circuit (IC) devices. The current high end IC (integrated circuit) technology node in manufacturing is 20 nm and looking toward 16 and 10 nm nodes to fulfil market demand. A series of chemically amplified resists (CARs) based on co and terpolymers of 4-hydroxystyrene (HOST), 2-ethyl-2-adamantyl methacrylate (EAMA) and/or a monomer-bound anionic photoacid generator (PAG) were prepared and characterized. Specifically, Triphenylsulfonium salt 4-(methacryloxy)-2,3,5,6-tetrafluorobenzenesulfonate (F4 PAG) was incorporated into the main chain to get PAG bound polymer microstructure.The aim of the study was to investigate interplay of individual monomers in co and terpolymer systems. This was achieved by understanding the reactivity ratios and monomer sequence distribution in the polymer. Analysis was conducted by using a software PROCOP version2.3. The co/terpolymer compositions were determined by quantitative ¹H NMR spectra. The copolymer reactivity ratio of each monomer was determined with Fineman–Ross, Kelen–Tüdös, and nonlinear least-squares curve- fitting methods. It was observed that EAMA is not polymerizable under given reaction conditions and copolymerization of EAMA-PAG was also not possible. HOST-EAMA system yielded reactivity ratios near zero indicating that they form quasi alternating structures. HOST-PAG system yielded copolymers rich in PAG. On the basis of the reactivity ratios determined from the binary copolymers, Alfrey–Goldfinger equations were used to estimate the compositions of the terpolymers. In terpolymer system, where two monomers were non homopolymerizable, both PAG and EAMA competed to add up to the HOST radical. All six reactivity values were less then unity indicating preferred cross propagation of radicals. PAG was the most reactive monomer. Monomer sequence distribution of copolymer and terpolymer was established to get an idea of detailed microstructure of the chain. Copolymers confirmed 84% of dyads formation of each monomer while terpolymer analysis revealed dominance of HOST centered triads. In addition to this, kinetics of terpolymerization reaction was performed to validate the theory. Findings from the study can be used to tailor make CAR synthesis for optimum EUV (extreme ultraviolet) lithography performance.

Graphical abstract

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Controlled cationic polymer particles prepared by dispersion polymerizations using poly(l-lysine) macromonomers as a stabilizer

Publication date: 2 June 2017
Source:Polymer, Volume 118
Author(s): Tomomichi Itoh, Shingo Okada, Katsuaki Kojima, Hironori Asano, Hiroaki Shimomoto, Eiji Ihara
A novel poly(l-lysine) macromonomer was successfully prepared via a click reaction between vinyl benzyl azide and propargyl-terminated poly(l-lysine), and it was used as a functional stabilizer for the dispersion polymerization of styrene; narrowly distributed polystyrene particles were produced as a result, onto which cationic poly(l-lysine) chains were grafted. The resulting particles exhibited a pH-responsive dispersion behavior in aqueous solutions due to the properties of the poly(l-lysine) chains at the particle surface. It was found that the particle size and the surface density of the resultant particles could be varied by tuning the concentrations of the macromonomer, styrene, and initiator used in the initial solution of the dispersion polymerization. The poly(l-lysine) macromonomer was also found to be effective when used as a stabilizer for the dispersion polymerization of both methyl methacrylate and a styrene/acrylonitrile mixture.

Graphical abstract

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PELP1 - A Key Mediator of Estrogen Signaling and Actions in the Brain

Abstract

Proline-, Glutamic acid-, and Leucine-rich Protein 1 (PELP1) is an estrogen receptor (ER) coregulator protein identified by our collaborative group. Work from our lab and others has shown that PELP1 is a scaffold protein that interacts with ERs, kinase signaling factors, as well as proteins involved in chromatin remodeling and DNA repair. Its role in mediating 17β-Estradiol (E2) signaling and actions has been heavily studied in cancer cells, but only recently has attention turned to its role in the brain. In this review, we discuss the tissue, cellular and subcellular localization of PELP1 in the brain. We also discuss recent evidence from PELP1 forebrain-specific knockout mice that demonstrate a critical role of PELP1 in mediating both extranuclear and nuclear ER signaling in the brain, as well as E2-induced neuroprotection, anti-inflammatory effects, and regulation of cognitive function. Finally, the PELP1 interactome and unique gene network regulated by PELP1 in the brain is discussed, especially as it provides new insights into PELP1 biology, protein interactions, and mechanisms of action in the brain. As a whole, the findings discussed in this review indicate that PELP1 functions as a critical ER coregulator in the brain to mediate E2 signaling and actions.

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Y5 receptor signalling counteracts the anorectic effects of PYY3-36 in diet induced obese mice

Abstract

Peptide YY 3-36 (PYY3-36) is known as a critical satiety factor reducing food intake both in rodents and humans. While the anorexic effect of PYY3-36 is thought to be mediated mainly by the Y2 receptor, the involvement of other Y-receptors in this process has never been conclusively resolved. Amongst them the Y5 receptor (Y5R) is the most likely candidate to also be a target for PYY3-36 which is thought to counteract the anorectic effects of Y2R activation. Here we show that short term treatment of diet induced obese WT and Y5R knockout mice (Y5KO) with PYY3-36 leads to significantly reduced food intake in both genotypes, which is more pronounced in Y5R KO mice. Interestingly, chronic PYY3-36 infusion via minipumps to WT mice causes increased cumulative food intake, which is associated with increased body weight gain. In contrast, lack of Y5R reversed this effect. Consistent with the observed increased body weight and fat mass in WT treated mice, glucose tolerance was also impaired by chronic PYY3-36 treatment. Again this was less affected in Y5KO mice suggestive of a role of Y5R's in the regulation of glucose homeostasis. Taken together, our data suggests that PYY3-36 mediated signalling via Y5 receptors may counteract the anorectic effects that it mediates via the Y2 receptor (Y2R) consequently lowering bodyweight in the absence of Y5 signalling. These findings open the potential of combination therapy using PYY3-36 and Y5R antagonists to enhance PYY3-36′s food intake reducing effects.

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Severity strata for EASI, mEASI, oSCORAD, SCORAD, ADSI and BSA in adolescents and adults with atopic dermatitis

Abstract

Background

Scoring systems for assessing the signs of atopic dermatitis (AD) are complex and difficult to interpret. Severity strata are helpful to properly interpret these assessments. We sought to confirm previously reported strata for Eczema Area and Severity Index (EASI), Scoring AD (SCORAD) and objective component of SCORAD (oSCORAD) and develop strata for the modified EASI (mEASI), Atopic Dermatitis Severity Index (ADSI) and body surface (BSA) for use in adults with AD.

Methods

Skin-examination was performed in 673 adolescents and adults (age ≥13 years) with diagnosed AD in a dermatology practice setting. Strata were selected using an anchoring approach based on a 4-point Investigator's Global Assessment of severity (clear of active skin lesions, mild, moderate or severe disease).

Results

We determined potential severity strata for EASI (0=clear, 0.1-5.9=mild, 6.0-22.9=moderate, 23.0-72=severe; kappa=0.694), mEASI (0-0.9=clear, 1-8.9=mild, 9.0-29.9=moderate, 30.0-90=severe; kappa=0.71), oSCORAD (0-7.9=clear, 8.0-23.9=mild, 24.0-37.9=moderate, 38.0-83=severe; kappa=0.70), SCORAD (0-9.9=clear, 10.0-28.9=mild, 29.0-48.9=moderate, 49.0-103=severe; kappa=0.68), ADSI (0-1.9=clear, 2-5.9=mild, 6.0-8.9=moderate and 9.0-15=severe; kappa=0.55), and BSA (0=clear, 0.1-15.9=mild, 16.0-39.9=moderate, 40.0-100=severe; kappa=0.656). oSCORAD >0 were found in clear skin due to the presence of xerosis, which is scored in oSCORAD. Similarly, SCORAD >0 were found in clear skin due to the scoring of xerosis, pruritus and sleeplessness. Similarly, mEASI and ADSI scores >0 occurred in patients with clear skin due to scoring of pruritus.

Conclusions

We recommend using these strata for interpretation of their respective measures in clinical trials of AD. There are important differences between the 5 assessments, which profoundly impact the interpretation of their scores.

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Sirolimus therapy for children with problematic Kaposiform haemangioendothelioma and tufted angioma

Abstract

Kaposiform haemangioendothelioma (KHE) and tufted angioma (TA) are rare vascular tumours that typically present during infancy or childhood. Originally regarded as distinct lesions, they are now considered as part of a spectrum. Presentation is usually as an enlarging, tender, blue or red mass. Both KHE and TA may be associated with Kasabach-Merritt Phenomenon (KMP), a severe haemorrhagic state arising from intralesional platelet trapping, microangiopathic haemolytic anaemia, and consumptive coagulopathy.

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Treatment satisfaction and need for shared decision-making in patients with psoriasis from Peru

Abstract

psoriasis is reported by the World Health Organization as a chronic skin disease with an elevated physical, emotional and socioeconomic burden. However, this burden is underestimated in developing countries, such as Peru, due the lack of epidemiological research in dermatology. This uncertainty hinders the development of appropriate patient-centered health care that prevent patients from unnecessary suffering.

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